1. Field of the Invention
The present invention relates to a control apparatus of a high speed/high quality printer, and more particularly to a control apparatus for controlling a printing of characters or the like with dot patterns modified in the high speed/high quality printer.
2. Description of the Prior Art
Generally, in a printer used in a computer and so on, there is occationally performed a modification such as an enlargement and italicization of a letter or character to a dot pattern of the letter or character to be printed. Such a modification is performed, for example, in a case where a partial phrase or word of a sentense is desired to be emphasized in expression. For example, Japanese patent laid-open publication No. 187558/1985 teaches a method of modifying a letter font in which a standard font corresponding to a dot pattern of a letter is prepared and when data associated with a desired font of the letter to be printed is provided it is compared with the standard font data of the letter to be in turn modified on the basis of the comparison.
FIG. 2 is a diagram used for the explanation of data flow in a conventional control apparatus of the printer. The control apparatus shown in FIG. 2 is provided with a receiving buffer 1, CG (Character Generator) memory 3 and an image buffer 5. The receiving buffer 1 comprises RAM (Random Access Memory) etc., and temporarily stores data received from a host apparatus. CG memory 3 stores dot pattern data representing a character to be printed. The image buffer 5 comprises RAM etc., and temporarily stores a unit quantity of data of dot pattern to be printed.
In a receiving processing P1a, character data corresponding to a character to be printed is received from a host apparatus, and stored in the receiving buffer 1. In a decoding modification processing P3a, a decoding of the character data is performed, and the associated dot pattern data is taken out from CG memory 3.
Thereafter, it is determined whether it is necessary for the dot pattern data to be subjected to a modification processing, and if necessary, the modification processing is performed. As an example of such a modification processing, there is the processing of the enlargement, the italicization and so on as mentioned before.
FIGS. 3A-3C are diagrams used for the explanation of a procedure of the enlargement of a character, respectively. FIG. 3A is a view showing an example of a dot pattern which represents a part of some character. Now let's consider this dot pattern is to be enlarged twice in a holizontal direction in the figure.
First, as shown in FIG. 3B, on the basis of OR operation on the adjacent dots in a holizontal direction there are provided dots at positions extended half dot on the left and right sides, respectively. As a result, one dot in FIG. 3A becomes three dots mutually overlapped on the left and right sides. In printing, since there is no overlapping of the dots, the central dots are removed, respectively, and the enlarged figure as shown in FIG. 3C will be printed.
FIG. 4 is a diagram used for the explanation of a procedure of the italicization of a character or letter. A letter shown in FIG. 4 shows a length of vertical straight line. In order to provide the italicization of this segment of a character, for instance, the dots aligned in a vertical direction are shifted in order on the basis of unit of blocks each comprising four dots in the right direction in the figure by a mutually different predetermined length. It is possible to compress the thus italicized segment in the left and right directions. In a case where the italicized segment is enlarged, further blocks each comprising four dots are added to the associated blocks on the right side, respectively. Further, it is possible to compress the thus enlarged italic segment of a character.
There is a problem with this type of apparatus as mentioned above however. Recently, there are performed not only reletively simpler modifications as shown in FIGS. 3A-3C and FIG. 4 as mentioned above, but also a more sophisticated modification, since a user tends to strongly require a higher quality of character printing. For example, a character to which the modification processings as shown in FIGS. 3A-3C and FIG. 4 have been performed is required to be subject to a smoothing processing to be smoothed in the contour thereof to be improved in quality, or readability.
Such a smoothing processing is complicated and takes much more time for the processing. Thus, there is such a problem that a processing ability is extremely degraded with a conventional scheme in which the modification processing is first performed immediately before printing.